Thanks to everyone who replied with helpful information and advice on the W210.

I went ahead and bought the '98 E320 with 104K miles that I was looking at. It had two previous owners, both elderly people, who took great care of it. It was garage kept for most of its time and has been regularly dealer serviced, including replacement of the crank position sensor, transmission pilot bushing, transmission fluid changes and many other part replacements so looks like it has been well cared for. No signs of rust, so I think if I get it rustproofed it should be O.K.

I agree with RunningTooHot's comment on driveability--compared to my 300D and W124, this car is very different to drive--it's smoother on the road and has somewhat more of a "big car" feel to it.

So, I'm looking forward to owning it thanks again to all of you and this forum for the extremely valuable repair advice I've gotten for these cars.